Host computer digital signal processing system for communicating over voice-grade telephone channels

• US 5,646,983 A
• Filed: 03/25/1993
• Issued: 07/08/1997
• Est. Priority Date: 03/25/1993
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: US Robotics Access Corp. (US Robotics Incorporated)
• Inventors: Norrell, Andrew L., Suffern, Robert C.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): PALAN, STEPHEN C
• Application Number:
  US08/037,075
• Time in Patent Office: 1,566 Days
• Field of Search: 379/93, 379/96, 379/97, 379/98, 379/88, 379/89, 375/8, 375/9, 375/122
• US Class Current: 379/93.32
• CPC Class Codes: H04M 1/656 for recording conversations
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• CPC Class Codes: H04M 11/066 Telephone sets adapted for data transmision
• CPC Class Codes: H04M 3/493 Interactive information services, e.g. directory enquiries ; Arrangements therefor, e.g. interactive voice response [IVR] systems or voice portals
• CPC Class Codes: H04M 3/533 Voice mail systems

Abstract

A conventional computer is coupled to an analog telephone transmission link by an analog/digital conversion interface adapter. Modem transmission is accomplished by performing the modulation and demodulation functions digitally in the computer'"'"'s existing processor which executes programs which transfer data between the computer'"'"'s memory and the interface adapter. Using the same interface adapter and existing processor, the arrangement may be used to send and receive images in the form of standard V.29 format facsimile data, to send and receive data operating as a synchronous IBM 3270 compatible terminal device, or to record and play back conventional voice transmissions rather than data to implement a telephone answering, voice message handling, and telemarketing systems.

Claims

1. In combination with a computer of the class comprising, in combination:

a microprocessor,

a random access memory,

a system bus composed of data and control conductors interconnecting said microprocessor and said memory,

a direct memory access controller connected to said bus for supervising data transfers to and from said memory via the said system bus independently of the operation of said microprocessor, and

at least one expansion slot socket connected to said system bus,

an auxiliary circuit card for communicating between said computer and a remote device via a voice-band telephone circuit, said circuit card comprising, in combination;

an edge connector including a plurality of electrical terminals adapted for insertion into said at least one expansion slot socket to establish electrical connections to said system bus,

a hybrid circuit having a bi-directional telephone line port, and incoming port for delivery an incoming voice-band analog signal, and an outgoing voice-band port for receiving an outgoing voice-band analog signal,

a telephone line adapter circuit connected between said telephone circuit and said bi-directional line port of said hybrid circuit, said line adapter circuit including a hook switch for selectively connecting and disconnecting said telephone circuit and said line port in response to a first control signal, a loop-current detector for generating a second control signal indicating when an active connection has been established with said remote device, a ringing-signal detector for generating a third control signal indicating when ringing signals are being received over said telephone circuit, and circuit means for transmitting said first, second, and third control signals between said auxiliary circuit card and said system bus via said edge connector, an incoming sample data register connected to said edge connector,

an analog-to-digital converter connected between the incoming port of said hybrid circuit and said incoming sample data register for converting sample amplitudes of said incoming voice-band analog signal into incoming digital sample values which are temporarily stored in said incoming sample data register,

first control means for applying a direct memory access storage request signal to said edge connector for transmission via said bus to said direct memory access controller each time an incoming digital sample value is temporarily stored in said incoming data register to effect the transfer of said incoming sample value to said memory,

an outgoing sample data register connected to said edge connector,

a digital-to-analog converter connected between the outgoing port of said hybrid circuit and said outgoing sample data register for said outgoing voice-band analog signal,

second control means for applying a direct memory access read request signal to said edge connector for transmission via said bus to said direct memory access controller each time an sample value in said output register has been converted by said digital-to-analog converter, and

third control means applying an interrupt signal to said edge connector for transmission via said bus to said microprocessor each time a predetermined number of incoming digital values have been processed by said analog-to-digital converter.

3. An auxiliary circuit card as claimed in claim 1, further comprising, in combination:

a modem modulation routine executed by said microprocessor for translating digital data into said digital sample amplitude values; and

a modem demodulation routine executed by said microprocessor for translating said incoming digital sample values into digital data.

4. An auxiliary circuit card as claimed in claim 3 wherein said modem modulation and modem demodulation routines are stored in said memory.

5. An auxiliary circuit card as claimed in claim 1, wherein said remote device operates at a remote baud rate, said analog-to-digital converter converts said sample amplitudes into a first stream of incoming digital sample values at a sampling rate synchronized to a local clock signal, and said auxiliary circuit card further comprises, in combination:

an interpolation routine executed by said microprocessor for interpolating said first stream of incoming digital sample values and thereby producing a second stream of incoming digital sample values substantially synchronized to said remote baud rate;

a modem modulation routine executed by said microprocessor for translating digital data into said digital sample amplitude values; and

a modem demodulation routine executed by said microprocessor for translating said second stream of incoming digital sample values into digital data.

2. In combination with a computer of the class comprising, in combination, a microprocessor, a random access memory, expansion socket, and a system bus interconnecting said microprocessor, memory, and expansion socket, an arrangement for communicating between said computer and a remote device via a voice-band telephone circuit connecting to a telephone switching office, said arrangement comprising, in combination:

an auxiliary circuit card having an edge connector to engage said expansion socket, said auxiliary circuit card further comprising, in combination;

a telephone line adapter circuit connected to said telephone circuit, said line adapter circuit including a hook switch for selectively connecting and disconnecting said telephone circuit and said auxiliary circuit card in response to a first control signal, a loop-current detector for generating a second control signal indicating when an active connection has been established with said switching office, a ringing-signal detector for generating a third control signal indicating when ringing signals are being received over said telephone circuit from said switching office, and circuit means for transmitting said first, second, and third control signals between said auxiliary circuit card and said system bus,

a hybrid circuit, interconnected to said line adapter circuit and having a bi-directional line port, for communicating signals to and from said line adapter circuit along said bi-directional line port, and

signal conversion means connected between said bi-directional line port and said edge connector for translating an incoming analog signal from said hybrid circuit into incoming digitally-expressed values representative of the amplitude of samples of said incoming analog signal, for supplying said values to said bus via said edge connector, and for translating outgoing digital sample values received from said bus via said edge connector into a voice band analog signal for transmission to said hybrid circuit and over said telephone circuit, and

call progress control means for supervising the connection between said computer and said telephone circuit via said auxiliary circuit card, said call progress control means comprising, in combination;

means including a first set of instructions stored in said memory and executed by said microprocessor for applying a sequence of outgoing digital sample values to said bus which are representative of a sequence of dual dial-tone signals suitable for establishing a dial-up connection via said switching office to said remote device, and

means including a second set of instructions stored in said memory and executed by said microprocessor for processing said incoming digitally-expressed sample values to detect the presence of an answer tone received over said telephone circuit from said switching office.

6. In combination with a computer of the class comprising, in combination, a microprocessor, a random access memory, and a system bus composed of data and control conductors interconnecting said microprocessor and said memory, an auxiliary circuit for communicating in real time between said computer and a remote device via a voice band telephone circuit, said remote device operating at a remote baud rate, said auxiliary circuit comprising, in combination:

a hybrid circuit having a bi-directional telephone line port, an incoming port for delivering an incoming voice-band analog signal, and an outgoing voice-band port for receiving an outgoing voice-band analog signal;

a telephone line adapter circuit connected between said telephone circuit and said bi-directional line port of said hybrid circuit, said line adapter circuit including a hook switch for selectively connecting and disconnecting said telephone circuit and said line port in response to a first control signal, a loop-current detector for generating a second control signal indicating when an active connection has been established with said remote device, a ringing-signal detector for generating a third control signal indicating when a ringing signal is being received over said telephone circuit, and circuit means for transmitting said first, second and third control signals between said auxiliary circuit and said system bus;

an incoming sample data register interconnected to said system bus;

an analog-to-digital converter connected between the incoming port of said hybrid circuit and said incoming sample data register for converting sample amplitudes of said incoming voice-band analog signal into a first stream of incoming digital sample values which are temporarily stored in said incoming sample data register, said analog-to-digital converter sampling said amplitudes at a sampling rate synchronized to a local clock signal;

an interpolation routine executed by said microprocessor for interpolating said first steam of incoming digital sample values and thereby producing a second stream of incoming digital sample values substantially synchronized to said remote baud rate;

a modem demodulation routine executed by said microprocessor for translating said second stream of incoming digital sample values into digital data;

an outgoing sample data register interconnected to said system bus;

a modem modulation routine executed by said microprocessor for translating digital data to said digital sample amplitude values, said digital sample amplitude values being temporarily stored in said outgoing sample data register;

a digital-to-analog converter connected between the outgoing port of said hybrid circuit and said outgoing sample data register for converting digital sample amplitude values in said outgoing sample data register into said outgoing voice-band analog signal;

a call answering routine executed by said microprocessor when said incoming voice-band analog signal comprises an analog voice signal from a remote caller, for (i) transmitting a voice acknowledgement over said voice-band telephone circuit by transferring a predetermined set of outgoing digital sample values from a storage medium to said digital-to-analog converter to transmit a voice signal over said voice-band telephone circuit, and thereafter (ii) recording an incoming voice message received over said voice-band telephone circuit by storing a set of digital values representative of said analog voice signal on a storage medium;

a tone-dialing routine executed by said microprocessor for applying a sequence of outgoing digital sample values to said bus which are representative of a sequence of dual dial-tone signals suitable for establishing a dial-up connection to said remote device; and

an answer-tone detection routine executed by said microprocessor for processing said incoming digital sample values to detect the presence of an answer tone received over said voice-band telephone circuit.

7. An auxiliary circuit as claimed in claim 6, wherein said interpolation, modem demodulation, modem modulation, call-answering, tone-dialing and answer-tone detection routines are stored in said memory.

8. An auxiliary circuit as claimed in claim 6, wherein said incoming voice-band analog signal comprises graphical data from a facsimile transmission device.

9. In combination with a computer of the class comprising, in combination, a microprocessor, a random access memory, and a system bus interconnecting said microprocessor and memory, an arrangement for communicating in real time between said computer and a remote device via a voice band telephone circuit interconnected to a telephone switching office, said remote device operating at a remote baud rate, said arrangement comprising, in combination:

(a) an auxiliary circuit communicating with said system bus, said auxiliary circuit further comprising, in combination;

(i) a telephone line adapter circuit connected to said telephone circuit, said line adaptor circuit including a hook switcher for selectively connecting and disconnecting said telephone circuit and said auxiliary circuit in response to a first control signal, a loop-current detector for generating a second control signal indicating when an active connection has been established with said switching office, a ringing-signal detector for generating a third control signal indicating when a ringing signal is being received over said telephone circuit from said switching office, and circuit means for transmitting said first, second, and third control signals between said auxiliary circuit card and said system bus,

(ii) a hybrid circuit, interconnected to said line adapter circuit and having a bi-directional line port, for communicating signals to and from said line adapter circuit along said bi-directional line port, and

(iii) signal conversion means interconnected to said bi-directional line port for translating an incoming analog signal from said hybrid circuit into incoming digitally-expressed values representative of the amplitude of samples of said incoming analog signal, for supplying said values to said bus, and for translating outgoing digital sample values received from said bus into a voice band analog signal for transmission to said hybrid circuit and over said telephone circuit, said signal conversion means including interpolation, demodulation and modulation routines executed by said microprocessor;

(b) call progress control means for supervising the connection between said computer and said telephone circuit via said auxiliary circuit, said call progress control means comprising, in combination;

(i) means including a first set of instructions stored in said memory and executed by said microprocessor for applying a sequence of outgoing digital sample values to said bus which are representative of a sequence of dual dial-tone signals suitable for establishing a dial-up connection via said switching office to said remote device, and

(ii) means including a second set of instructions stored in said memory and executed by said microprocessor for processing said incoming digitally-expressed sample values to detect the presence of an answer tone received over said telephone circuit from said switching office; and

(c) a call answering routine executed by said microprocessor, when information being communicated over said voice-band analog circuit comprises an analog voice signal from a remote caller, for (i) transmitting a voice acknowledgement over said voice-band telephone circuit by transferring a predetermined set of outgoing digital sample values from a storage medium to said digital-to-analog converter to transmit a voice signal over said voice-band telephone circuit, and thereafter (ii) recording an incoming voice message received over said voice-band telephone circuit by storing a set of digital values representative of said analog voice signal on a storage medium.

10. An arrangement as claimed in claim 9, wherein said interpolation, demodulation and modulation routines are stored in said memory.

11. In combination with a computer of the class comprising, in combination, a microprocessor, a random access memory, a system bus composed of data and control conductors interconnecting said microprocessor and said memory, and a direct memory access controller interconnected to said bus for supervising data transfers to and from said memory via said system bus independently of the operation of said microprocessor,

an auxiliary circuit for communicating in real time between said computer end a remote device via a voice band telephone circuit, said auxiliary circuit comprising, in combination:

a hybrid circuit having a bi-directional telephone line port, an incoming port for delivering an incoming voice-band analog signal, and an outgoing voice-band port for receiving an outgoing voice-band analog signal;

a telephone line adapter circuit connected between said telephone circuit and said bi-directional line port of said hybrid circuit, said line adapter circuit including a hook switcher for selectively connecting and disconnecting said telephone circuit and said line port in response to a first control signal, a loop-current detector for generating a second control signal indicating when an active connection has been established with said remote device, a ringing-signal detector for generating a third control signal indicating when a ringing signal is being received over said telephone circuit, and circuit means for transmitting said first, second and third control signals between said auxiliary circuit and said system bus;

an incoming sample data register interconnected to said system bus;

an analog-to-digital converter connected between the incoming port of said hybrid circuit and said incoming sample data register for converting sample amplitudes of said incoming voice-band analog signal into incoming digital sample values, said incoming digital sample values being temporarily stored in said incoming sample data register;

an outgoing sample data register interconnected to said system bus; and

a digital-to-analog converter connected between the outgoing port of said hybrid circuit and said outgoing sample data register for converting digital sample amplitude values in said outgoing sample data register into said outgoing voice-band analog signal.

12. An auxiliary circuit as claimed in claim 11, wherein said remote device operates at a remote baud rate, said analog-to-digital converter converts said sample amplitudes into a first stream of incoming digital sample values at a sampling rate synchronized to a local clock signal, and said auxiliary circuit further includes an interpolation routine executed by said microprocessor for interpolating said first stream of incoming digital sample values and thereby producing a second stream of incoming digital sample values substantially synchronized to said remote baud rate.

13. An auxiliary circuit as claimed in claim 12, further comprising:

a modem demodulation murine executed by said microprocessor for translating said second stream of incoming digital sample values into digital data; and

a modem modulation routine executed by said microprocessor for translating digital data to said digital sample amplitude values, said digital sample amplitude values being temporarily stored in said outgoing sample data register.

14. An auxiliary circuit as claimed in claim 13, further comprising a call answering routine executed by said microprocessor when said incoming voice-band analog signal comprises an analog voice signal from a remote caller, for (i) transmitting a voice acknowledgement over said voice-band telephone circuit by transferring a predetermined set of outgoing digital sample values from a storage medium to said digital-to-analog converter to transmit a voice signal over said voice-band telephone circuit, and thereafter (ii) recording an incoming voice message received over said voice-band telephone circuit by storing a set of digital values representative of said analog voice signal on a storage medium;

a tone-dialing routine executed by said microprocessor for applying a sequence of outgoing digital sample values to said bus which are representative of a sequence of dual dial-tone signals suitable for establishing a dial-up connection to said remote device; and

an answer-tone detection routine executed by said microprocessor for processing said incoming digital sample values to detect the presence of an answer tone received over said voice-band telephone circuit.

15. An auxiliary circuit as claimed in claim 14, wherein said modulation, demodulation, interpolation, call-answering, tone-dialing and answer-tone detection routines are stored in said memory.

16. An auxiliary circuit as claimed in claim 15, further comprising a first control means for applying a direct memory access storage request signal via said bus to said direct memory access controller each time an incoming digital sample value is temporarily stored in said incoming sample data register to effect the transfer of said incoming sample value to said memory.

17. An auxiliary circuit as claimed in claim 16, further comprising a second control means for applying a direct memory access read request signal via said bus to said direct memory access controller each time an sample value in said outgoing sample data register has been converted by said digital-to-analog converter.

18. An auxiliary circuit as claimed in claim 17, further comprising a third control means for applying an interrupt signal via said bus to said microprocessor each time a predetermined number of incoming digital values have been processed by said analog-to-digital converter.

19. An auxiliary circuit as claimed in claim 13, wherein said incoming voice-band analog signal comprises graphical data from a facsimile transmission device.

20. An auxiliary circuit as claimed in claim 13, further comprising, in combination, a call answering routine executed by said microprocessor when said incoming voice-band analog signal comprises an analog voice signal from a remote caller, for (i) transmitting a voice acknowledgement to said remote caller by transferring a predetermined set of outgoing digital sample values from a storage medium to said digital-to-analog converter to transmit a voice signal over said voice-band telephone circuit, and thereafter (ii) recording an incoming voice message received over said voice-band telephone circuit by storing a set of digital values representative of said analog voice signal on a storage medium.

21. An auxiliary circuit as claimed in claim 13, further comprising, in combination:

a tone-dialing routine executed by said microprocessor for applying a sequence of outgoing digital sample values to said bus which are representative of a sequence of dual dial-tone signals suitable for establishing a dial-up connection to said remote device; and

an answer-tone detection routine executed by said microprocessor for processing said incoming digital sample values to detect the presence of an answer tone received over said voice-band telephone circuit.

22. A method for communicating between a computer system and a remote device via a voice band telephone circuit, said remote device operating at a remote baud rate,

said computer system comprising, in combination:

(i) a microprocessor,

(ii) a random access memory,

(iii) a system bus composed of data and control conductors interconnecting said microprocessor and said memory,

(iv) a hybrid circuit having a bi-directional telephone line port, an incoming port for delivering an incoming voice-band analog signal, and an outgoing voice-band port for receiving an outgoing voice-band analog signal,

(v) a telephone line adapter circuit connected between said telephone circuit and said bi-directional line port of said hybrid circuit, said line adapter circuit including a hook switch for selectively connecting and disconnecting said telephone circuit and said line port in response to a first control signal, a loop-current detector for generating a second control signal indicating when an active connection has been established with said remote device, a ringing-signal detector for generating a third control signal indicating when a ringing signal is being received over said telephone circuit, and circuit means for transmitting said first, second and third control signals between said auxiliary circuit and said system bus,

(vi) an incoming sample data register interconnected to said system bus,

(vii) an analog-to-digital converter connected between the incoming port of said hybrid circuit and said incoming sample data register,

(viii) an outgoing sample data register interconnected to said system bus, and

(ix) a digital-to-analog converter connoted between the outgoing port of said hybrid circuit and said outgoing sample data register, said method comprising, in combination, the following steps;

operating said analog-to-digital converter at a sampling rate synchronized to a local dock signal to convert sample amplitudes of said incoming voice-band analog signal into a first stream of incoming digital sample values;

temporarily storing said incoming digital sample values in said incoming sample data register;

operating said microprocessor to execute an interpolation routine stored in said memory, so as to interpolate said first stream of incoming digital samples values to thereby produce a second stream of incoming digital sample values substantially synchronized to said remote baud rate;

operating said microprocessor to execute a modem demodulation routine stored in said memory, so as to translate said second stream of incoming digital sample values into digital data;

operating said microprocessor to execute a modem modulation routine stored in said memory, so as to translate digital data to digital sample amplitude values;

temporarily storing said digital sample amplitude values in said outgoing sample data register;

operating said digital-to-analog converter to convert said digital sample amplitude values in said outgoing sample data register into said outgoing voice-band analog signal;

detecting a ringing signal received over said voice-band telephone circuit from a remote caller when information being received over said voice band telephone circuit comprises an analog voice signal; and

operating said microprocessor, responsive to said detection of said ringing signal from a remote caller, to (i) transmit a voice acknowledgement to said remote caller by transferring a predetermined set of outgoing digital sample values from a storage medium to said digital-to-analog converter to transmit a voice signal over said voice band telephone circuit, and to (ii) record an incoming voice message from said remote caller by storing a set of digital values representative of said analog voice signal on a storage medium.

23. A method as claimed in claim 22, further comprising, in combination, the following steps:

operating said microprocessor to execute a tone-dialing routine stored in said memory, so as to apply a sequence of outgoing digital sample values to said bus which are representative of a sequence of dual dial tone signals suitable for establishing a dial-up connection to said remote device; and

operating said microprocessor to execute an answer-tone detection routine stored in said memory, so as to process said incoming digital sample values to detect the presence of an answer tone received over said voice-band telephone circuit.